Many entertainment control systems have recently been made with MIDI capabilities. The MIDI format allows many different kinds and types of information to be communicated--including information about the music being played and/or something associated with that music. MIDI's popularity is due, at least in part, to its great communications capability. MIDI allows entertainment control systems to communicate status and receive information from other MIDI-equipped devices.
Musical instruments often are connected by a MIDI connection to a controller. The controller can monitor the settings of the musical instruments, including the notes they play, its tone, and other things. FIG. 1 shows, for example, synthesizer 100 connected by a MIDI connection 102 to MIDI controller 104. Controller 104 monitors the notes and information which is output from synthesizer 100.
MIDI can also be used as a control technique. For example, controller 104 can control synthesizer 108 instrument 110 via MIDI cable 106.
Despite MIDI's great power, it is a relatively simple protocol. All messages that are sent over cable 106 are received by both of the controlled units 108, 110. That is to say, MIDI's communications is dependent on the wired connection between devices. This means that MIDI in general is contrary to the usual complexity of conventional networking techniques. In a usual network technique, logical connections need to be made between devices after the cabling has been attached. MIDI uses the cabling itself to make these logical connections.
MIDI musical data is arranged as a stream of events occurring at specified intervals. The following is a typical stream of MIDI data:
Header format=0 ntrks=1 division=240 PA0 Track start PA0 Delta time=0 Time signature=3/4 MIDI-clocks/click=24 32nd notes/24-MIDI -clocks=8 PA0 Delta time=0 Tempo, microseconds-per-MIDI-quarter-note=41248 PA0 Delta time=0 Meta Text, type=0.times.01 (Text Event) leng=23 PA0 Delta time=480 Note on, chan=1 pitch=67 vol=88 PA0 Delta time=0 Note on, chan=2 pitch=62 vol=72 PA0 Delta time=0 Note on, chan=3 pitch=59 vol=88 PA0 Delta time=240 Note off, chan=4 pitch=43 vol=64 PA0 Delta time=0 Note off, chan=3 pitch=59 vol=64 PA0 Delta time=0 Note off, chan=2 pitch=62 vol=64 PA0 Delta time=0 Note off, chan=1 pitch 67 vol=64 PA0 Delta time=0 Note on, chan=1 pitch=67 vol=81 PA0 Delta time=0 Note on, chan=2 pitch=62 vol=75 PA0 Delta time=0 Note on, chan=3 pitch=59 vol=88 PA0 Delta time=0 Note on, chan=4 pitch=55 vol=60 PA0 Delta time=240 Note off, chan=4 pitch=55 vol=64 PA0 Delta time=0 Note off, chan=3 pitch=59 vol=64 PA0 Delta time=0 Note off, chan=2 pitch=62 vol=64 PA0 Delta time=0 Note on, chan=2 pitch=64 vol=58 PA0 Delta time=0 Note on, chan=3 pitch=60 vol=78 PA0 Delta time=1920 Meta Text, type=0.times.01 (Text Event) leng=7
Text =&lt;Chorale #001 in G Major&gt; PA1 Text=&lt;Fermata&gt;
Each line in the stream is an event. For example, in the line "Delta time=240 Note off, chan=4 pitch=43 vol=64," the phrase "Delta time=240" means that the line starts executing 240 MIDI-clocks of time after the last line started executing. "Note off" indicates that the note presently being played by channel, i.e., voice "4" is to be turned off.
There are also many MIDI flavors. One such flavor is the so-called MIDI show control. MIDI show control uses its own addressing capability.
While MIDI is simple and effectual for the above reasons, the inventor noticed that MIDI has some disadvantages. MIDI data can only travel in one direction through a MIDI cable. Hence, a first, one-directional MIDI cable 102 receives information from the synthesizer and a different one-directional MIDI cable 106 sends the information to the synthesizer. Bi-directional communication hence, requires separate cables. Moreover, the MIDI protocols are generally limited to 15 feet in length and the relatively slow data rate of 31.25K Baud. While MIDI hardware is relatively inexpensive, this has limited its usefulness.
"MIDI thru" connectors can be used to extend data transmission distances. This uses a daisy chaining technique whereby a cable is input to a device, sent through appropriate electronics, and output from the device.
In view of the above limitations, it is an object of the present invention to improve MIDI's functionality while maintaining its usefulness. In order to carry out this objective, the present invention modifies MIDI in a way to maintain its advantages, but to attenuate its disadvantages. The preferred mode of the present invention converts the MIDI signals into a protocol which is compatible with existing network techniques, preferably Ethernet. Ethernet is well-known as a peer-to-peer connection scheme. The present invention uses a technique of configuring the Ethernet protocol in a way which is more MIDI-like. This enables MIDI techniques and communications to be used over an Ethernet link.
It should be understood that while the preferred mode of the present invention uses Ethernet hardware, other existing network hardware could alternately be used. Ethernet is preferred because of its simplicity and wide dissemination. However, the inventor contemplates that other network formats could also be used using the teaching of the present invention. An important feature of the present invention is its use of standard off-the shelf hardware for most of the functions that are carried out.